1. Field of the Invention
The present invention relates to a fuel cell and a fuel cell connecter.
2. Description of the Related Art
A fuel cell mounted in an electric or hybrid vehicle or the like is formed by stacking a large number of electric power generation units, each referred to as a cell (a single cell), into numerous layers. Each of the single cells comprises an electrolyte membrane made of an ion exchange membrane which is sandwiched by an anode and a cathode on the respective sides and further by a pair of separator on both outer sides thereof. A path is defined on the separator for supplying fuel gas, such as hydrogen gas, and oxidant gas, such as oxygen gas, to the anode and the cathode, respectively. Fuel and oxidant gases supplied through the path cause chemical reaction inside the cell, which generates power.
For such a fuel cell, management of the power generation state for each single cell is necessary in order to control the amounts of supplied fuel and oxidant gases and to find a faulty cell. To enable such management, the generation voltage for each single cell is monitored so that the control is carried out based on the monitored generation voltage. Generally, a connecter 100 comprising a housing 10, as shown in FIG. 9, inside which detection terminals (not shown) are arranged at intervals equal to those of the separators of the plurality of single cells, is used. FIG. 9 is a perspective view of such a connecter 100, viewed from diagonally above the rear surface X. Openings 12 are defined on the rear surface X of the housing 10 in conformity with the arrangement of the detection terminals. Penetration slits (not shown) are formed on the bottom surface Y of the housing 10 with a pitch corresponding to the arrangement of the detection terminals. The penetration slits are available for connecting the electrode of each single cell and each detection terminal when mounting the connecter 100 in the fuel cell 102 described below.
The housing 10 has legs 14 formed thereon. Each leg 14 has a hook-like projecting engagement portion 16 formed thereon. The connecter 100 is mounted in the fuel cell 102, as shown in FIG. 10. The fuel cell 102 has a resin hook portion 20 formed thereon. With the hook portion 20 engaged with the engagement portion 16 of the connecter 100, the connecter 100 is fixed to the fuel cell 102. The fuel cell 102 also has a tension plate 22 formed on the top surface A thereof, which extends in the direction in which the single cells are stacked. Electrical wires 18 connected to each of the detection terminals of the connecter 100 are securely fixed on the tension plate 22.
Here, the electrode of the fuel cell to which the detection terminal in the connecter is to be connected is made of carbon. When a carbon electrode is employed, each single cell must be formed relatively thicker in consideration of the need to provide sufficient structural strength or the like. However, there is an increasing demand for thinner single cells in conjunction with the recent improvement in efficiency of power generation by a singe cell used in a fuel cell, and power generation by a thinner single cell becoming possible.
When single cells having a thinner width as described above are employed and the connecters 100 are mounted side by side, regions where the housings 10 of the adjacent connecters 100 spatially interfere with each other (the hatched portion in FIG. 11) are formed, as shown in FIG. 11. This leads to a program that the connecter 100 cannot be properly mounted.
Meanwhile, when the outer wall of the housing 10 is formed thinner to avoid such interference, insufficient structural strength is provided for the connecter, which leads to problems of decreased manufacturing efficiency of the connecters and more frequent breakage of the connecters during mounting or installation.